1. Field of The Invention
The present invention relates generally to a recording/reproducing apparatus within which different tape cassettes of different sizes are installable. Specifically, the present invention relates to such recording/reproducing apparatus of minimizing tension difference forced on a recording tape housed in the respective tape cassette.
2. Description of The Background Art
Recently, it has been developed that a compatible type of recording/reproducing apparatus within which different tape cassettes having different distance from a supply to take-up reels between which a recording tape is wound are installable. The reels respectively have reel mounts movable between two positions according to the type of tape cassette installed. Generally, in such compatible type of recording/reproducing apparatus, tape tension is regulated by mechanically regulating braking of the supply reel mount, or by electrically controlling voltage applied to a driving motor of the supply reel mount, i.e., controlling motor torque.
However, tape tension cannot be maintained constantly from the top to the end thereof by the mechanical regulation system. Commonly, according to decrease of winding diameter at the tape end, tape tension is rapidly increased. Therefore, in a small tape cassette having a pair of hubs of small diameter, tape tension is rapidly increased at the tape end comparing to that of a large tape cassette having hubs of larger diameter. On the other hand, amount of tape housed in the small tape cassette is lesser than that of the large one, therefore, maximum winding diameter of the tape reel of the small tape cassette becomes smaller than that of the large one. Accordingly, when the small tape cassette is installed in the apparatus, tape tension alters gradually but becomes large. As a result, tape tension of the small tape cassette at the tape end is higher than that of the large one to cause tape damage and unstable tape loading. Similar problems have been occurred when tape tension is electrically regulated. In addition, when utilizing electrical regulation, control apparatus to control the driving voltage of the driving motor of the reel mount becomes complicated.